This application relates to methods of manufacturing and mounting a printed circuit board in a receiving socket such that electrical leads on the printed circuit board maintain good electrical connections with pins in the receiving socket. In particular, the application is concerned with creating a mounting structure that will ensure good electrical connections are maintained even when the assembly is subjected to significant levels of shock and vibration.
A printed circuit board (PCB) both mechanically supports and electrically connects electronic components. A PCB may include one or more non-conductive layers which provide mechanical support and electrical separation/insulation for one or more conductive layers. The one or more conductive layers, for example, may include any electrically conductive material such as copper, silver, aluminum, etc. The conductive layers may be formed on the PCB in patterns that allow leads of selected electrical components that are mounted on the PCB to be electrically connected to one another.
FIGS. 1A and 1B illustrate a related art PCB 1, and a mounting socket 2 that receives the PCB. The PCB 1 includes a substrate 11, electronic components 12, and a plurality of electrical leads 13 formed along the lower edge of the substrate 11. Electrical components 12 can be formed on both sides of the substrate. Likewise, separate electrical leads 13 may be formed on opposite sides of the substrate. Conductive layers or traces on the substrate electrically connect leads of the electrical components 12 to the electrical leads 13 on the bottom edge of the substrate.
The PCB is mounted in the socket 2 by pushing the lower edge of the PCB into a slot 22 formed between sidewalls 25 of the socket 2, as illustrated in FIG. 1B. Electrical contacts or pins in the slot 22 couple to the electrical leads 13 on sides of the bottom edge of the PCB 1. The socket may also include pivoting locking clips 21 that engage slots 15 on side edges of the PCB to hold the PCB 1 in the socket 2. When the locking clips 21 are pivoted outward away from the side edges of the PCB 1, they may exert an upward force on the bottom edge of the PCB 1 that tends to push the PCB 1 out of the slot 22 of the socket 2.
Unfortunately, when a PCB 1 and mounting slot 2 arrangement as shown in FIGS. 1A and 1B are subjected to significant levels of shock and vibration, the PCB 1 can move with respect to the mounting socket 2. This movement of the PCB 1 can cause an electrical connection between the electrical leads 13 on the bottom edge of the PCB 1 and contacts in the slot 22 to be broken temporarily broken or impaired. Although contact between the electrical contacts 13 and the leads in the slot 22 may not be completely broken, movements of the PCB 1 with respect to the mounting slot 22 may cause the electrical resistance of the connection to vary over time. And this change in electrical resistance alone could cause problems for signals traversing the connection. As a result of these factors, when such an assembly is subjected to significant shock and vibration, it is common for an electrical computing system using this arrangement to report faults or errors, or completely stop responding.